This specification relates to light source detection from synthesized faces, for example, analyzing an image to detect a type and a relative location of a light source that illuminated an object in the image at the instant that the image was captured.
Information gathering agencies can use a variety of techniques for identifying a type and a location of a light source that illuminate a subject of a photograph. One such technique may include taking multiple photographs of the subject from different angles, followed by measuring the length of shadows cast by the subject in the respective photographs for each corresponding angle. Typically, analyzing the shadow-length measurements can be based on an assumption about the type of illuminating source: directional light or point light. Iterative testing of various locations where a point source or a directional source may have been placed may eventually lead to determining a light source location that best reproduces the shadow-length measurements.